In subsea applications, for example subsea oil production, there may be a need for sensing pressure or temperature in, for example, hydraulic conduits or vessels. However, sensors used in deep sea environments may be exposed to a very high pressure to be sensed in a range of up to, for example, 1,400 bar (or 20,000 PSI), a temperature in a range of, for example, −40° C. to +205° C., and an environmental pressure of, for example, 350 bar (or 5,000 PSI). Corresponding requirements for such sensors in drilling and production equipment of petroleum and natural gas industries are defined in international standards, for example in NS-EN ISO 10423:2009/API 6A. However, the requirements defined in these standards may be difficult to fulfil.
Therefore, up to now these kinds of sensors have frequently been manufactured and delivered with pressure containing parts that do not fully comply to these standards and a request for concession has been accepted for each project using these sensors. Conventional sensors may thus not achieve the desired protection against the large pressure differences that can prevail between the high process pressure in the hydraulic conduit, pipeline or vessel, and the ambient pressure, which is still relatively high in a subsea environment.